/Engine/Source/Runtime/Core/Public/Misc/DateTime.h
Uses strftime-like syntax: a - Weekday, eg) Sun A - Weekday, eg) Sunday w - Weekday, 0-6 (Sunday is 0) y - Year, YY Y - Year, YYYY b - Month, eg) Jan B - Month, eg) January m - Month, 01-12 d - Day, 01-31 e - Day, 1-31 l - 12h Hour, 1-12 I - 12h Hour, 01-12 H - 24h Hour, 00-23 M - Minute, 00-59 S - Second, 00-60 p - AM or PM P - am or PM j - Day of the Year, 001-366
String representation.
[FString](API\Runtime\Core\Containers\FString) ToFormattedString ( const TCHAR * Format ) const